Bolster supporting spring unit



Aug. 30, 1938.

D. F. SPROUL BOLSTER SUPPORTING SPRING UNIT Filed Jan. 16, 1936 IIIIIII time A... 3 m 2,128,505

UNITED STATES PATENT OFFICE 2,128,565 SUPPORTING SPRING UNIT Donald F. Spronl, Chicago, 11]., assignor to Cardwcll-Weatinghousc Company, a corporation of Application January 16, 1936, -8erial No. 59,427

' v 9 Claims. (Cl. 267-4)) This invention relates to resilient friction de- Referring now to the drawing, the reference vices and more particularly bolster springs or character 0 designates a railway car truck havsupporting units for railway bolsters. ing a bolster opening it in the side frame thereof One of the objects of. the invention is the prothroughwhich one endof the bolster ll extends. vision of a new and improved spring unit for The bolster ii is mounted to slide vertically in [supporting railway truck bolsters having novel the opening in the usual manner. As is common means for frictionally resisting the compression in such constructions,a spring assembly or nest of the unit. of springs I2 is interposed between the bolster Another object of the invention is the proand a spring plank it carried by the side frame. vision of'a new and improved bolster supporting Since the details of the truck frame and truck 10 spring unit having novel means for frictionally constitute no part of the present invention, it is resisting the compression of the spring and for not thought necessary to further .illustrate or limiting/ the expansion thereof. describe the same.

A further object of the invention isthe 'pro- The present device or spring unit It is of such vision of snow and improved bolster supporting dimensions that it may besubstituted for one of unit that is simple in construction, efficient ,in the conventional bolster supporting helical operation, composed of few parts and that'may springs l5. This spring supporting unit It combe readily installed in the conventional bolster prises the friction members It and I1, each of supporting spring assembly. which has a cap or base portion it and a conf Other and further objects and advantages of centric cylindrical portion is extending outthe invention will appear from. the following dewardly therefrom, surrounded by a flange l0.

-scription taken in cb'nnection with the accom- Since the friction members It and II are duplipanying drawing in which cates, the lower one only need be described.

F154 4L8. side elevation of a railway truck The base portion It is provided with a center showing the invention in position beneath the p nin 2 w h is adapted to receive the .bol ster of the truck 'with parts broken away? volitional positioning-111s o t e spring p te o Fig. 2 is a vertical section of the device on line spring plank for positioning the spring unit. The

2-2 of Fig.3; cylindrical portion it extends about the opening Fig. 3 is a horizontal section on line 3-2 of 2| and has its upp r or ope end providiid w Fig. 2; a pair of beveled or wedging faces Hand 22!! 0 Fig. 4 1 a perspective view of the friction on its inner surface, Each facing inwardly and shoes; and upwardly as shown in Figs. 2 and'5 of the draw- Fig. 5 is a perspective view of one of the fricing. These wedging faces may be considered as tion members. g segments of cylinders arranged at an angle to It is common practice to support the bolsters ch other as hown in F 2 nd Ah of railway trucks by a nest of helical springs nular portion .of theinner surface of the cylinbeneath each end of the bolster. These springs drical portion is is removed, that is, an annular are free acting and unless means be provided recess 2il-is provided, to form an annular shoulfor resisting free vibration of thesprings, the 23 a the base i h n l n d w dsins vibration thereof, under certain conditions, may faces 21 n w h are adapted t e en- 4 continue to build up, as when the, natural period gazed by Mu flanges r luss on the friction of vibration of the springs synchronizes with the Shoes for limiting the expansion of the u movement of the truck over the rail Joints, or as will pr sently app arwith the vertical vibration of the truck due to A pair o fr t on sho s 24 d e av n flat surfaces on the surfaces of the wheel treads. w t may b t m d pp sit y ra d ri tion 1 These vibrations have been known to build up to surfaces, that is, an upp inclined ds ns face such a stage as to cause serious injury as when 26 facing outwardly andupwa'rdly, and a lower they cause the springs to go solid on compresinclined wedglng face 21 facing outwardly and sion under heavy load, thereby causing breakage downwardly, Fig. 4, is interposed between the frlc-' of the truck frames and with light loads caustion members I8 and il in such a manner that 5 ing derailment of the wheels. the wedge or inclined faces 28 and 21 engage the The present invention seeksto eliminate this corresponding wedge faces 22 and 220 respecdifilculty by theprovision of new and improved tively, of said friction members. Each of the means for dampening the vibrations of the freefriction'shoes ,2 and 25 are provided at their acting springs. ends with flanges" and 28 whichare adapted to engage the shoulders 23 on the friction members for limiting the expansion of the unit. Each of the shoes'2 l and 25 have their outer surfaces curved transversely to correspond with the curvature of the inner surfaces of the wedge faces of the friction members.

Suitable means are provided for forcing the shoes into frictional contact with the wedge faces of the wedge members. Asshown, a single helical spring 3B is employed for this purpose and is arranged transversely of the axis of the unit. Each of the shoes is preferably provided with a spring seat 3! for positioning the spring.

The unit is provided with resilient means for assisting in supporting the load and also for returning the parts to expanded position upon re'-,

lease after the unit has been compressed. As shown, a helical spring 32 is-employed for this purpose. This spring surrounds the friction members and engages the flanges 80.

It will thus be seen that upon compresslonof the gear, the shoes will be forced inwardly against the spring 30, and its increasing resistance to compression as the unit is compressed will cause an increasing friction between the shoes and the friction surfaces 22 and 220. Since the ends of the shoes are free to move radially and the spring is arranged along the transverse axis of the two shoes, there will be substantially the same frictional resistance between the two ends of the shoes and the cooperating friction surfaces 22 and 220. Upon release of the gear, the spring 32 expands the gear until the flanges 28 and 25 enage the shoulders 23 which limit further expansion.

Means are provided for taking the overload for protecting the spring 32 from the unit is compressed. This may be accomplished in any one of three ways. The friction shoes 26 and 25 may be of such length that they will engage the bases of the friction members l6 and i1 before the inner ends of the friction members I6 and. i1 engage or vice versa. Or, if desired, these parts may all engage simultaneously, thus making an exceedingly solid column for taking the overload when the unit is compressed. The latter arrangement is shown.

Instead of thesingle transverse spring 30 for forcing the shoes apart into frictional engagement with the friction surfaces 22 and 220 of the friction members it and ii, a plurality of springs may be employed for this purpose.

It is thought from the foregoing taken in connection with the accompanying drawing that the construction and operation of my device will be apparent to those skilled in the art and that changes in size, shape, proportion and details of construction may be made without departing from the spirit and scope of the appended claims.

I claim as my invention:-

' 1. A cylindrical base member havinga flange extending about its lower portion, a cylindrical going solid when bolster supporting member having a flange extending about its upper end, the adjacent ends of said cylindrical members having their inner surfaces inclined outwardly to form wedging surfaces comprising segments of cylinders, a plurality of shoes having inclined friction surfaces in the form of segments of cylinders engaging the inclined surfaces of said members, resilient meansextending transversely to said shoes and tending to separate the same, and a spring surrounding said members and engaging said flanges for resisting the compression of said unit.

2. In a truck bolster supporting spring unit,

\ greases a pair of cylindrical friction members having flanges on their outer ends, each member having on the inner surface of its inner end'inclined wedging surfaces at opposite sides of said member, curved in cross-section, a pair of friction shoes having wedge faces on their ends engaging said wedgin'g surfaces, each of said shoes having spring seats on its inner side walls between the ends thereof, spring means engaging said seats, and a spring surrounding said cylindrical members and engaging said flanges.

3. A bolster supporting unit, comprising a pair of friction members, each having a base and a cylindrical portion'extending inwardly from the base, each cylindrical portion having its interior surface at its open end flared outwardly to form a Wedging friction surface comprising a segment of a cylinder, a plurality of shoes, each having members spaced apart, each base member having a flange extending about the same and an inwardly extending cylindrical member having inclined friction surfaces comprising a segment of a cylinder, a plurality of friction shoes each having inclined friction surfaces corresponding to the friction surfaces of said cylindrical members at each end thereof engaging the friction surfaces of said cylindrical members, cooperat ing dances and shoulders on said shoes and base members for limiting the separation of said base members, resilient means for forcing said shoes radially outwardly, and a spring extending about said cylindrical members and engaging said flanges for resisting the compression of the unit.

5. In a bolster supporting unit, a pair of cylindrical friction members having inclined friction surfaces, 8. pair of shoes each tapered toward each end to form double wedge surfaces for telescoping lnto and frictionaliy engaging the inclined friction surfaces of said members, resilient means comprising a helical spring arranged transversely to the axis of said unit for forcing saidshoes outwardly into frictional engagement with said members, springv means surrounding said shoes and friction members for resisting the compression of said unit, and interlocking means between said shoes and friction members for limitingthe separation of said members.

6. In a bolster supporting unit, a pair of hollow friction members each having an abutment at one end and having its inner surface at its other end inclined to form segmental cylindrical wedging surfaces, a flange extending about the outer end of each member, a pair of shoes each tapered on its outer surface toward each end frictionally engaging the wedging faces of said friction members, said shoes having protections extending radially outwardly for engaging said abutments for limiting the expansion of said unit, resilient means surrounding said shoes and members and engaging said flanges for returning the parts to normal position after compression, and resilient means for normally yieldingly forcing said shoes diametrically outward into frictional resistance with said members.

7. In a bolster supporting unit, a pair of hollow friction members each having fan abutment anaasos at one end and having its inner surface at its other end inclined to form a segmental cylindrical wedging surface, a pair of shoes each tapered on its outer surface toward each end frictionally engaging members, said ing radially outwardly for shoes having projections extendengaging said abutments for limiting the expansion of said unit, re-

silient means for returning the parts to normal position after compression, a helical spring extending transv rsely to the axis of said unit for yieldingly forci said shoes into frictional resistance with'said members, and means for limiting the compression of said resilient means.

' 8. In a bolster supportingunit, a pair of cylindrical friction members having inclined fric=,

tion surfaces, each of saidsu'rzfaces being a-segment of a cylinder, shoes frictionally engaging the wedging faces of said friction the inclined friction surfaces of said members, resilient means interior of said shoesfor forcing said shoes into frictional engagement with said members, and spring means for returning the parts to normal position after compression.

9. In a truck bolster supporting spring unit, a pair of cylindrical friction members having wedge surfaces comprising segments of cylinders on the interior surface of their adjacent ends,

a pair of wedge shoes, each having oppositely arranged wedging faces curved transversely of the shoes, a single transversely arranged spring en- -gaging the central portions of said shoes and extending transversely of the shoes, and resilient means for restoring the parts to normal positionafter compression. 

